The Season for Powertrains of the Future

"Guess our cars will be burning hydrogen pretty soon," said a nearby diner at Old Siam, a Thai restaurant here in Ann Arbor. "BMW has a new model with a hydrogen-powered V-12 that goes 188 mph."

Such is the spike in pseudo-knowledge about powertrain technology that occurs every January as the local radio and TV shows are filled with breathless snippets from the Detroit auto show.

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BMW did indeed show its rather bulbous H2R concept, which set nine international speed records last fall, powered by a hydrogen-fueled 282-hp, 6.0-liter V-12 adapted from the 760 sedan. The Munich-based company has been experimenting with hydrogen-powered piston engines for years and recently announced it would manufacture a version of the current 7-series sedan that could run on either gasoline or hydrogen.

Since pure hydrogen contains no carbon, combustion produces no unburned hydrocarbons, carbon monoxide, or carbon dioxide. And BMW says it has calibrated the engine to avoid the production of oxides of nitrogen as well.

Sounds great, except for the usual difficulties of using hydrogen as a fuel. The H2R carries 24 pounds of hydrogen in liquid form in a big super-thermos next to the driver. Liquid hydrogen is the densest form of the fuel, but the insulated tank required to hold it at 423 degrees below zero is necessarily heavy and bulky. Moreover, it takes roughly six kilowatt hours of electricity to liquefy each pound of hydrogen. Generated in a coal-fired plant, that quantity of electrical energy creates about as much carbon dioxide as you'd get by burning half a gallon of gasoline, which contains the same energy as that pound of liquid hydrogen. That's no way to solve global warming.

Fuel cells extract more performance from hydrogen than do internal-combustion engines. Detroit saw the debut of the General Motors Sequel. This machine is the latest development of GM's fuel-cell concept that places all of the vehicle's major mechanical and electrical bits in a foot-thick platform at the bottom of the vehicle. The Sequel has a practical-looking SUV body atop this platform. GM claims it goes 0 to 60 mph in 10 seconds and has a range of 300 miles.

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This performance is achieved using an 80-hp motor driving the two front wheels and a 34-hp electric motor mounted in the hub of each rear wheel. The electricity to power these motors comes from a GM fuel cell, coupled to a battery pack to achieve added hybrid efficiency.

The hydrogen to power the Sequel is stored in three large cylinders located in the car's thick platform. The tanks look to be about five feet long and perhaps 10 inches in diameter. Pressurized to 10,000 psi, they hold just 18 pounds of hydrogen.

Compressing hydrogen to 10,000 psi requires about a third of the energy that liquefying it does, but the ultra-pressure tanks are large and expensive. Moreover, their filling operation is hardly leak tolerant.

Whether you burn hydrogen or power a fuel cell with it, you must still produce the stuff. Today, 96 percent of the world's hydrogen comes from natural gas, oil, or coal—fossil fuel, in other words. Producing hydrogen for vehicular use from fossil fuel creates just as much pollution as burning gasoline does. For the details of why this is so, read The Hype About Hydrogen by Joseph Romm, an Energy Department official who oversaw hydrogen and fuel-cell research during the Clinton administration.

That's why, in realistic near-term discussions about energy conservation, hybrids and diesels rule the roost. At the Detroit show, Ford announced it would take the hybrid technology from the Escape SUV and soon transfer it to the Escape's newest sibling, the Mercury Mariner, as well as to the Ford Fusion mid-size sedan in 2006 along with its Mercury counterpart. GM meanwhile announced a joint venture with DaimlerChrysler to collaborate on hybrid technology for various models in 2008.

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At Lexus, the RX400h is about to go on sale, and the division announced that a GS450h would join the mid-size luxury lineup by 2006. Moreover, we hear rumors that the top version of the next-generation LS430 will be a hybrid. "The performance of a V-12 with the fuel economy of a V-6" would sound plenty compelling, particularly if gas prices were to rise again.

European carmakers are much more comfortable employing diesel engines to improve fuel efficiency. Diesel-car sales are sky-high in Europe—75 percent in Austria. But the oil-burning engines still don't pass the U.S. Tier 2 exhaust emissions standards that all cars must meet by 2007. These strict standards will likely require that diesels, to reduce oxides of nitrogen, be fitted with special catalysts that use urea (extracted from bovine urine).

When I asked Burkhard Göschel, BMW board member for development and purchasing, how a diesel with the urea catalyst, a conventional oxidation catalyst, a particulate trap, a turbocharger, an intercooler, and a 20,000-psi direct-fuel-injection system could possibly be cheaper than a hybrid, which is essentially an electric motor hung onto a simple gas engine, he said a hybrid battery was extremely expensive and that BMW was exploring other approaches to "energy management," as he put it. Although he wouldn't reveal what BMW was working on, he did suggest powering a steam engine using the heat in an engine's exhaust. Sounds silly until you realize that over 40 percent of the energy in the gasoline burned by an internal-combustion engine is wasted as exhaust heat.

Other European automakers, however, are starting to come around on hybrids. Wolfgang Dürheimer, Porsche's R&D boss, acknowledges that his company is looking at a hybrid powertrain for the Cayenne. Mercedes is also talking about hybrid propulsion in its upcoming models.

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Powertrain technology has never been as advanced as it is today, and with increasing pressure to improve fuel efficiency—without sacrificing performance or reliability—we are going to see some interesting developments in the next few years. If you thought the transition from carburetors and distributors to fuel injection and engine management systems was revolutionary, you ain't seen nothin' yet.